arch/powerpc/boot/main.c

   1 /*
   2  * Copyright (C) Paul Mackerras 1997.
   3  *
   4  * Updates for PPC64 by Todd Inglett, Dave Engebretsen & Peter Bergner.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11 #include <stdarg.h>
  12 #include <stddef.h>
  13 #include "elf.h"
  14 #include "page.h"
  15 #include "string.h"
  16 #include "stdio.h"
  17 #include "ops.h"
  18 #include "gunzip_util.h"
  19 #include "flatdevtree.h"
  20 #include "reg.h"
  21
  22 extern char _start[];
  23 extern char __bss_start[];
  24 extern char _end[];
  25 extern char _vmlinux_start[];
  26 extern char _vmlinux_end[];
  27 extern char _initrd_start[];
  28 extern char _initrd_end[];
  29 extern char _dtb_start[];
  30 extern char _dtb_end[];
  31
  32 static struct gunzip_state gzstate;
  33
  34 struct addr_range {
  35         void *addr;
  36         unsigned long size;
  37 };
  38
  39 struct elf_info {
  40         unsigned long loadsize;
  41         unsigned long memsize;
  42         unsigned long elfoffset;
  43 };
  44
  45 typedef void (*kernel_entry_t)(unsigned long, unsigned long, void *);
  46
  47 #undef DEBUG
  48
  49 static int parse_elf64(void *hdr, struct elf_info *info)
  50 {
  51         Elf64_Ehdr *elf64 = hdr;
  52         Elf64_Phdr *elf64ph;
  53         unsigned int i;
  54
  55         if (!(elf64->e_ident[EI_MAG0]  == ELFMAG0       &&
  56               elf64->e_ident[EI_MAG1]  == ELFMAG1       &&
  57               elf64->e_ident[EI_MAG2]  == ELFMAG2       &&
  58               elf64->e_ident[EI_MAG3]  == ELFMAG3       &&
  59               elf64->e_ident[EI_CLASS] == ELFCLASS64    &&
  60               elf64->e_ident[EI_DATA]  == ELFDATA2MSB   &&
  61               elf64->e_type            == ET_EXEC       &&
  62               elf64->e_machine         == EM_PPC64))
  63                 return 0;
  64
  65         elf64ph = (Elf64_Phdr *)((unsigned long)elf64 +
  66                                  (unsigned long)elf64->e_phoff);
  67         for (i = 0; i < (unsigned int)elf64->e_phnum; i++, elf64ph++)
  68                 if (elf64ph->p_type == PT_LOAD)
  69                         break;
  70         if (i >= (unsigned int)elf64->e_phnum)
  71                 return 0;
  72
  73         info->loadsize = (unsigned long)elf64ph->p_filesz;
  74         info->memsize = (unsigned long)elf64ph->p_memsz;
  75         info->elfoffset = (unsigned long)elf64ph->p_offset;
  76
  77         return 1;
  78 }
  79
  80 static int parse_elf32(void *hdr, struct elf_info *info)
  81 {
  82         Elf32_Ehdr *elf32 = hdr;
  83         Elf32_Phdr *elf32ph;
  84         unsigned int i;
  85
  86         if (!(elf32->e_ident[EI_MAG0]  == ELFMAG0       &&
  87               elf32->e_ident[EI_MAG1]  == ELFMAG1       &&
  88               elf32->e_ident[EI_MAG2]  == ELFMAG2       &&
  89               elf32->e_ident[EI_MAG3]  == ELFMAG3       &&
  90               elf32->e_ident[EI_CLASS] == ELFCLASS32    &&
  91               elf32->e_ident[EI_DATA]  == ELFDATA2MSB   &&
  92               elf32->e_type            == ET_EXEC       &&
  93               elf32->e_machine         == EM_PPC))
  94                 return 0;
  95
  96         elf32ph = (Elf32_Phdr *) ((unsigned long)elf32 + elf32->e_phoff);
  97         for (i = 0; i < elf32->e_phnum; i++, elf32ph++)
  98                 if (elf32ph->p_type == PT_LOAD)
  99                         break;
 100         if (i >= elf32->e_phnum)
 101                 return 0;
 102
 103         info->loadsize = elf32ph->p_filesz;
 104         info->memsize = elf32ph->p_memsz;
 105         info->elfoffset = elf32ph->p_offset;
 106         return 1;
 107 }
 108
 109 static struct addr_range prep_kernel(void)
 110 {
 111         char elfheader[256];
 112         void *vmlinuz_addr = _vmlinux_start;
 113         unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
 114         void *addr = 0;
 115         struct elf_info ei;
 116         int len;
 117
 118         /* gunzip the ELF header of the kernel */
 119         gunzip_start(&gzstate, vmlinuz_addr, vmlinuz_size);
 120         gunzip_exactly(&gzstate, elfheader, sizeof(elfheader));
 121
 122         if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei))
 123                 fatal("Error: not a valid PPC32 or PPC64 ELF file!\n\r");
 124
 125         if (platform_ops.image_hdr)
 126                 platform_ops.image_hdr(elfheader);
 127
 128         /* We need to alloc the memsize: gzip will expand the kernel
 129          * text/data, then possible rubbish we don't care about. But
 130          * the kernel bss must be claimed (it will be zero'd by the
 131          * kernel itself)
 132          */
 133         printf("Allocating 0x%lx bytes for kernel ...\n\r", ei.memsize);
 134
 135         if (platform_ops.vmlinux_alloc) {
 136                 addr = platform_ops.vmlinux_alloc(ei.memsize);
 137         } else {
 138                 if ((unsigned long)_start < ei.memsize)
 139                         fatal("Insufficient memory for kernel at address 0!"
 140                                " (_start=%p)\n\r", _start);
 141         }
 142
 143         /* Finally, gunzip the kernel */
 144         printf("gunzipping (0x%p <- 0x%p:0x%p)...", addr,
 145                vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
 146         /* discard up to the actual load data */
 147         gunzip_discard(&gzstate, ei.elfoffset - sizeof(elfheader));
 148         len = gunzip_finish(&gzstate, addr, ei.memsize);
 149         printf("done 0x%x bytes\n\r", len);
 150
 151         flush_cache(addr, ei.loadsize);
 152
 153         return (struct addr_range){addr, ei.memsize};
 154 }
 155
 156 static struct addr_range prep_initrd(struct addr_range vmlinux,
 157                                      unsigned long initrd_addr,
 158                                      unsigned long initrd_size)
 159 {
 160         void *devp;
 161         u32 initrd_start, initrd_end;
 162
 163         /* If we have an image attached to us, it overrides anything
 164          * supplied by the loader. */
 165         if (_initrd_end > _initrd_start) {
 166                 printf("Attached initrd image at 0x%p-0x%p\n\r",
 167                        _initrd_start, _initrd_end);
 168                 initrd_addr = (unsigned long)_initrd_start;
 169                 initrd_size = _initrd_end - _initrd_start;
 170         } else if (initrd_size > 0) {
 171                 printf("Using loader supplied ramdisk at 0x%lx-0x%lx\n\r",
 172                        initrd_addr, initrd_addr + initrd_size);
 173         }
 174
 175         /* If there's no initrd at all, we're done */
 176         if (! initrd_size)
 177                 return (struct addr_range){0, 0};
 178
 179         /*
 180          * If the initrd is too low it will be clobbered when the
 181          * kernel relocates to its final location.  In this case,
 182          * allocate a safer place and move it.
 183          */
 184         if (initrd_addr < vmlinux.size) {
 185                 void *old_addr = (void *)initrd_addr;
 186
 187                 printf("Allocating 0x%lx bytes for initrd ...\n\r",
 188                        initrd_size);
 189                 initrd_addr = (unsigned long)malloc(initrd_size);
 190                 if (! initrd_addr)
 191                         fatal("Can't allocate memory for initial "
 192                                "ramdisk !\n\r");
 193                 printf("Relocating initrd 0x%lx <- 0x%p (0x%lx bytes)\n\r",
 194                        initrd_addr, old_addr, initrd_size);
 195                 memmove((void *)initrd_addr, old_addr, initrd_size);
 196         }
 197
 198         printf("initrd head: 0x%lx\n\r", *((unsigned long *)initrd_addr));
 199
 200         /* Tell the kernel initrd address via device tree */
 201         devp = finddevice("/chosen");
 202         if (! devp)
 203                 fatal("Device tree has no chosen node!\n\r");
 204
 205         initrd_start = (u32)initrd_addr;
 206         initrd_end = (u32)initrd_addr + initrd_size;
 207
 208         setprop(devp, "linux,initrd-start", &initrd_start,
 209                 sizeof(initrd_start));
 210         setprop(devp, "linux,initrd-end", &initrd_end, sizeof(initrd_end));
 211
 212         return (struct addr_range){(void *)initrd_addr, initrd_size};
 213 }
 214
 215 /* A buffer that may be edited by tools operating on a zImage binary so as to
 216  * edit the command line passed to vmlinux (by setting /chosen/bootargs).
 217  * The buffer is put in it's own section so that tools may locate it easier.
 218  */
 219 static char builtin_cmdline[COMMAND_LINE_SIZE]
 220         __attribute__((__section__("__builtin_cmdline")));
 221
 222 static void get_cmdline(char *buf, int size)
 223 {
 224         void *devp;
 225         int len = strlen(builtin_cmdline);
 226
 227         buf[0] = '\0';
 228
 229         if (len > 0) { /* builtin_cmdline overrides dt's /chosen/bootargs */
 230                 len = min(len, size-1);
 231                 strncpy(buf, builtin_cmdline, len);
 232                 buf[len] = '\0';
 233         }
 234         else if ((devp = finddevice("/chosen")))
 235                 getprop(devp, "bootargs", buf, size);
 236 }
 237
 238 static void set_cmdline(char *buf)
 239 {
 240         void *devp;
 241
 242         if ((devp = finddevice("/chosen")))
 243                 setprop(devp, "bootargs", buf, strlen(buf) + 1);
 244 }
 245
 246 struct platform_ops platform_ops;
 247 struct dt_ops dt_ops;
 248 struct console_ops console_ops;
 249 struct loader_info loader_info;
 250
 251 void start(void)
 252 {
 253         struct addr_range vmlinux, initrd;
 254         kernel_entry_t kentry;
 255         char cmdline[COMMAND_LINE_SIZE];
 256         unsigned long ft_addr = 0;
 257
 258         if (console_ops.open && (console_ops.open() < 0))
 259                 exit();
 260         if (platform_ops.fixups)
 261                 platform_ops.fixups();
 262
 263         printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
 264                _start, get_sp());
 265
 266         vmlinux = prep_kernel();
 267         initrd = prep_initrd(vmlinux, loader_info.initrd_addr,
 268                              loader_info.initrd_size);
 269
 270         /* If cmdline came from zimage wrapper or if we can edit the one
 271          * in the dt, print it out and edit it, if possible.
 272          */
 273         if ((strlen(builtin_cmdline) > 0) || console_ops.edit_cmdline) {
 274                 get_cmdline(cmdline, COMMAND_LINE_SIZE);
 275                 printf("\n\rLinux/PowerPC load: %s", cmdline);
 276                 if (console_ops.edit_cmdline)
 277                         console_ops.edit_cmdline(cmdline, COMMAND_LINE_SIZE);
 278                 printf("\n\r");
 279                 set_cmdline(cmdline);
 280         }
 281
 282         printf("Finalizing device tree...");
 283         if (dt_ops.finalize)
 284                 ft_addr = dt_ops.finalize();
 285         if (ft_addr)
 286                 printf(" flat tree at 0x%lx\n\r", ft_addr);
 287         else
 288                 printf(" using OF tree (promptr=%p)\n\r", loader_info.promptr);
 289
 290         if (console_ops.close)
 291                 console_ops.close();
 292
 293         kentry = (kernel_entry_t) vmlinux.addr;
 294         if (ft_addr)
 295                 kentry(ft_addr, 0, NULL);
 296         else
 297                 kentry((unsigned long)initrd.addr, initrd.size,
 298                        loader_info.promptr);
 299
 300         /* console closed so printf in fatal below may not work */
 301         fatal("Error: Linux kernel returned to zImage boot wrapper!\n\r");
 302 }